The present invention relates principally to multi-use apparatus for the control of portable power tools and to machine tools of similar function. Such power tools include for example, circular saws, routers, portable drill presses and sabre or jig saws. The invention finds use in all overhead radial applications (and other planes for example, vertical) and by use of a bench top converts to a fully functional table/rip saw, panel detail sizing saw, light spindle moulder and/or table sabre or jig saw.
Australian Patent Specifications 49665/79 and 499634 disclose apparatus that allow for example, a saw to be used in the overhead (work from above) application. Neither of these devices allow the tool used to function in a radial manner about the workpiece, instead, requiring the workpiece to be radially presented to the device at a required angle for the selected operation. Alternatively, it is necessary to relocate the entire device to the required angle. Both of these actions are very inconvenient when cutting varied angles on longer length material requiring support at both ends, especially when working to a length stop. Further, neither of these devices provide an accurate means by which the height of the power tool can be variably and finely controlled while maintaining a level attitude to a workpiece.
Another problem existing in radial devices of this nature is that reliably accurate angle selection is almost impossible to achieve with just one setting for two reasons.
One reason is the design usually incorporates a relatively small protractor, resulting in the marks indicating degrees being very closely spaced. Consequently, an almost imperceptible inaccuracy can be quite unacceptable at a point further from the point of axis and if applied, for example, to a rectangular frame with mitred corners that inaccuracy is then multiplied by the eight cuts required. Obviously the problem is further compounded when the point of axis becomes even slightly worn, because of the short radius to the set markings. The second contributing factor to this problem is in accurately relating the selected angle to the workpiece support and in turn, the workpiece to be cut. This problem is also due to the design, the front to rear orientation of existing devices of this nature causes the transverse location of the workpiece support in relation to angle setting to be governed over too short a span. (Ideally, accurate angle settings are better achieved if both arms of the angle are of equal length and the reading is taken as far as possible from the point of axis along one arm).
A further disadvantage with existing radial devices of this nature is that when it is desirable to present the cut from either edge of the workpiece at an adjustable amount and/or angle it cannot be done with convenience and/or safety. When such a variable presentation is required, it is necessary to end invert the workpiece for the desired cut. This is often undesirable and inconvenient.
There are many situations where an accurately adjustable width of cut would be highly desirable and a part remedy to this situation is available in the form of variable width trenching heads and "drunk" or "wobble" saws, as well as routers having whatever size cutter but if a number of cuts are needed that are to be wider than the maximum width setting of whatever type cutter is available there is no option with existing radial equipment except to relocate the material to the cutter again to increase the cut by the required amount. This is invariably inaccurate and inconvenient.
And further with existing prior art, when required, there is no convenient and automatic method of ensuring that such cuts or trenches are spaced evenly and accurately.
It has long been accepted by those needing to cut large panels that a reliably guided ripping and cross cutting capacity exceeding 1.2 meters is a virtual necessity but machines having these features are of considerable expense and not normally portable. This need is confirmed by the various methods used in trying to achieve these objectives at a relatively low cost. Australian Patent No. 499634, when inverted for use in the work from below configuration, as with other known devices, for example, table saws, is restricted by the size of the tabletop. To overcome this an extra table has been made available to extend the usable width for ripping of larger panels, consequently occupying considerable space in storage, transport and also when being used. There are other saw tables employing various methods of extending sections to accommodate this larger width of cut for ripping. However, none of these provide at low cost, a reliable and automatic realignment with the saw blade. Neither do they provide at low cost, an accurate method of guided crosscutting to 1.2 meters wide or more.
The machines that do have this crosscutting capacity normally employ a sliding table to guide the workpiece, being very acceptable but the method of design and construction has made the cost quite prohibitive to those not having a constant need for the function and is inherently heavy affecting portability. There are still others that make this function available in the form of an attachable kit still being quite expensive and inconvenient as well as affecting portability.
Further, with existing radial/table devices of this nature, size and shape are not suited to portability or being handled and setup by one man, as well as taking up considerable space in storage and/or transport.
The present invention provides a multi use power tool control apparatus that seeks to substantially overcome or lessen these disadvantages and preferably is incorporated in a compact quick knockdown and fold up portable form.